Persons who have suffered a knee injury or undergone knee surgery often require extensive physical therapy to rehabilitate the damaged muscles and ligaments. To date, a number of devices have been developed to assist in such therapy. Johnston, U.S. Pat. No. 5,253,639, Johnston, U.S. Pat. No. 5,286,242 and Fontaria, U.S. Pat. No. 5,324,245 disclose therapeutic devices designed to stretch the knee joint. However, each of these products requires the use of a fairly complicated pulley mechanism that must be operated by the patient while in either a seated (Johnston '639) or prone (Johnston, '242 and Fontana) position. Each of these devices exhibits a fairly complicated construction. Moreover, it is apt to be unduly strenuous and awkward for patients undergoing therapy to operate these devices. In Johnston '242 and Fontana, not only must the patient lie on his or her stomach, he or she must exert all of the operating force that is required to operate the device.
Mattox et al., U.S. Pat. No. 4,699,376, discloses a hip and joint exercising apparatus wherein the user's leg is positioned in an engaging member that is slidably mounted to an elongated tube. The tube provides frictional resistance to the engaging member. Unfortunately, this apparatus does not permit stretching of the knee. Such stretching is usually required for full knee therapy and rehabilitation.
Harvey, U.S. Pat. No. 5,074,549, discloses a knee stretching device that employs a rectangular frame. This product does not require that the user operate a pulley-type mechanism. However, the patient must use his or her hands and arms to hold the frame in position. As a result, this device could be both overly strenuous and awkward to use.